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                [Cqoi2014]危桥                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
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                                <h3>题目描述</h3><p><p><span style="font-size: medium">Alice和Bob居住在一个由N座岛屿组成的国家，岛屿被编号为0到N-1。某些岛屿之间有桥相连，桥上的道路是双<br />
向的，但一次只能供一人通行。其中一些桥由于年久失修成为危桥，最多只能通行两次。Alice希望在岛屿al和a2之间往返an次（从al到a2再从a2到al算一次往返）。同时，Bob希望在岛屿bl和b2之间往返bn次。这个过程中，所有危桥最多通行两次，其余的桥可以无限次通行。请问Alice和Bob能完成他们的愿望吗？<br />
</span></p></p><hr/><h3>输入格式</h3><p><p><br />
<font size="4">本题有多组测试数据。<br />
每组数据第一行包含7个空格隔开的整数，分别为N、al、a2、an、bl、b2、bn。<br />
接下来是一个N行N列的对称矩阵，由大写字母组成。矩阵的i行j列描述编号i一1和j-l的岛屿间的连接情况，若为&ldquo;O&rdquo;则表示有危桥相连：为&ldquo;N&rdquo;表示有普通的桥相连：为&ldquo;X&rdquo;表示没有桥相连。<br />
|</font></p></p><hr/><h3>输出格式</h3><p><p><font size="4">对于每组测试数据输出一行，如果他们都能完成愿望输出&ldquo;Yes&rdquo;，否则输出&ldquo;No&rdquo;。</font></p>
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<p><br />
</p></p><hr/><h3>样例输入</h3><pre>4 0 1 1 2 3 1
XOXX
OXOX
XOXO
XXOX
4 0 2 1 1 3 2
XNXO
NXOX
XOXO
OXOX
</pre><hr/><h3>样例输出</h3><pre>Yes
No
数据范围
 4<=N<50
 O<=a1, a2, b1, b2<=N-1
 1 <=an.  b<=50
</pre><hr/><h3>提示</h3><p>没有写明提示</p><hr/><h3>题目来源</h3><p>没有写明来源</p>
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